Many electronic devices employ clocked sequential systems. Microprocessors, for example, typically have internal state machines that change in response to a periodic clock signal. The electronic devices often do not generate the clock signal, but instead receive a master clock signal from an external clock generator. Clock signals supplied by a clock generator are of two general types: single-ended and differential. A single-ended clock signal propagates upon a single electrical channel, and periodically changes from a low voltage to a high voltage, compared to a reference voltage such as circuit ground. A differential clock signal, by contrast, propagates on two channels simultaneously, and is defined by the difference between the voltages on the two channels. A more common type of differential clock signal propagates with the voltages on the two channels having substantially the same periodic waveform but being one hundred eighty degrees out of phase with each other. In another form of differential clock signal, one channel carries a periodic signal and the other channel carries a constant reference voltage set at the mid-swing voltage of the periodic clock signal.